Active past and future:
Sara revised the document
Sara will revise the document

Passive past and future:
The document was revised by Sara
The document will be revised by Sara.

Underline all verbs that express past action only.

1. Three methods were considered, and it was decided that ultrafiltration was the best method.
2. They decided that ultrafiltration was the best method.
3. With ultrafiltration, whey is concentrated by passing it through a semipermeable membrane.
4. Ultrafiltration concentrates whey when whey is passed through a semipermeable membrane.

Underline the form of the verb to be with one line and the past participle with two lines.

1. Once the image quality and mission requirements have been established, this knowledge can be translated into specifications for the sensor.
2. Noise inhibits all algorithms in their ability to distinguish differences between details.
3. The sensitivity with respect to image quality can be determined by repeated experiments with a variety of algorithms.
4. The algorithms impact the total sensor system design and encompass the processing hardware requirements.

Revise the following sentences by converting passive voice constructions to active voice ones.

1. Brief hotel descriptions and rates are also given in the brochure.

2. The organizational test is met by the articles of incorporation and bylaws of the corporation.

3. To maintain its tax-exempt status, the foundation must be organized and operated for exempt purposes.

4. The second form of variation is broken down into four types of variation, setup variation, order quantity variation, operation variation, and scrap labor variation.